Telephone system.



I F. M. SLOUGH- TELEPHONE sysrsm.

APPLICATION fILED APE 28, I916- RENEWED FEB- 3' i917.'

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x is I an iron, I

ro STROMBERG-CARLSON TELEPHONE roaa'rron' or new YORK.

. FRANK IVL sLonei-r, or noonnsrnn, N W YORK, ASSIGNOR, BY Assreiviunirrs, MFG. 00., or eoonnsrnn, NEW YonK, A non TELEPHONE SYSTEM.

' Specification of Letters Patent. Pat nt d NOV 27, 19

Application filed April28, 1916,'Seria1 No. 94,107. .Renewed February 3, 1917. Serial No. 146,516.

- To allwhom it may concern:

Be itknown that I, FRANK M. SLoUGrr, a citizen of the. United States, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Telephone Systems; and I do hereby declare the following to bee full, clear, and exact descrip tion of the invention, such as will enable others skilled in the art to which it appertains to-make and use the same.

My invention relates to telephone systems, and more particularly to such systems as are set forth in a companion application Ser.'No. 35,013, filed June 19, 1915.

The objects of the present invention are to provide meansin connection with the ringing keys to break down an established connection, in order that another connection may be set up. I also aim to provide means to indicate for which party the connection is set up. I also provide means which enable the operatorat any time to ascertain for which party the connection is set up.

Other objects of my invention and the invention itself will probably be better understood from a description of an embodiment ofthe invention.

3 The drawing is a diagram of a portion ofa telephone system showing an embodi ment of my invention.

Referring now to the drawing, at I is in dicated a telephone line which will be re ferred to as the called-line. At II is the main or central station whereat the switchboard is installed, and whereat means are provided for connecting telephone lines together. In the form shown this connecting means. consists of a cord circuit shown generally at W. A second telephone line is shown at III. Both the lines I and" III lead to the station II where they terminate in the elements of switching means. In the embodiment shown apparatus is provided for connecting the means W to the telephone lines,here shown as switches P-J and P,J which are preferably plugs and jacks. on the lines. On the line I I have shown, for convenience, but a single substation,

illustrated generally at X, which includes a transmitter, receiver, receiver switch-hook and a signal. For convenience, I have illus trated upon the line III four substations Y, Z, U and V. At one of these only Ihave Substation apparatus is connected illustrated 1 in detail the substation apparatus, which is of the same character in general as: that shown at the substation X. The talking set of the other substations,

adapted to produce currents of particular characteristics designedto operate the signals upon the line III. The numerous lamps, relays, keys, etc, shown at the main station, will be understood, as well as their operations, from a. description of the operation of the system.

In general, the operation of the system is as follows: When the subscriber at X initiates a call, the lamp31 is operated in the usual manner and the plug P inserted into the jack, resulting, among other things, most of which are understood, in theoperation of the relay 5 whichconnects the operators set to the cordand the apparatus shown in the lower right=hand corner of the figure with the other portions of the cord. To call the first party, the operator then in serts thelplug P into the jack J, and ringing current is supplied from the machine B, through the magnet 130, in a well known manner. when the subscriber resp0nds,.the ringing current will be disconnected from the line and the talking circuit completed, all of which is understood. At the end of the/conversation, the plugs are withdrawn from the jacksand the apparatus restored to normal, as is well understood.

To call the second party, the key a is operated, causing the energization of the relays Gand H. The relay G locks up and completes a, circuit for the lamp Z which indicates to theoperator. for which, party the connections are set up. The relay .I'I completes the connection of the ringing generator It, to the cord circuit, It, being designed to produce current which will operate the bell at the second station.

To call the third party, the key b is operated, which completes circuits for the relays I and L. These relays lock up, the re lay. I completing a. circuit for the lamp d,

llltl and the relay L connecting the ringing ge e or R3 to .the rd- :W i i desire ,t ocel th our p r -y,

"both "(1, and b are pushed, allot the relays G, H, I and L are energized, each locks up and circuits are completed for the lamps (Z2 an h rins n ma hi I "It will be seen that each time a ringing connection is set up; that ,is,.each time the.

ringing generator the'connection's are set up. The operation of the lamp indicates to the operator at all :times-foi'wlilc'li character 01'' current the central station apparatus is prepared to place upon :the line. I have shown lamps'at 86, (LIZ, and (Z as being the most convenient form of signal, though it WlllbB understood that any suitable form a may be used. It will also be seen that the :key K is each time connected vup to the lamp whose illuminationwou'ld indicate the ringing current for which the connection is set up, so that the operator can always test to ascertain what the arrangement, or for what character of current the apparatus is prepared. a

The provision of the :keys 300 and 301,

and theswitches 7 3 and 74 controlled thereby, enable the operator to upset or break down any ringing current connection which has been completed. It sometimes happens that the operator will, through inadvertence or mistake, set up the central station apparatus preparingit to furnish the wrong kind of current; that is, ior'example, she

may set it up to supply current from the generator R upon the line when the third party is desired. The apparatus '73, 74, 300

and 301 is employed to enable her to be able to break down any established connection in order that she may correct the error.

I A detailed operation of the system illus trated in the drawing is as follows: Assunr ing the subscriber at X on the line I desires to talk to the subscribers on the line III, first, the subscriber at Y, the subscriber at X removes the receiver from the switch-hook21, which rising, closes a switch 21'22 and completes a circuit as follows: ground 23, switch 24rconductor 25 20- 22-- 21- conductor 26 switch 27 line relay 1 battery 28 to ground 29. The relay 1 will become energized, closing the switch 30 in the circuit of the line lamp 31 and causingthe same to light over a circuit from ground 32 -31- 30- 28 29. The line lamp and its associated parts are located at the main or central station III, where there are ,also a number of cordsfone of which-is shown at The operator connects the cord vto the line by inserting the plug"? intothe jack J-of the line, the tip contact 33, sleeve contact 34 and ringing contact engaging respectively with the I 36 of the jack, A circuit will be completed through,thema-gnets of the relays-2 and 3, as follows: from ground 37 through bat- I tery 38 magnet of 3' 36 magnet of2 to ground 39. The magnet of 2 will be energized, opening the, switches 2,4: and 27 and cutting off the'line relay and line lamp 81 of the'line I, so that they are now disconnected from that "line and will not in any wayencumber the system during inture operation: The magnet of .3 will be energized, closing a switch 40 and completing a circut through the winding of the slow acting relay-5,.as follows: ground 41 switch 40-Tconductor 42 winding of 5 switch 43 -battery 4-1 to ground 45. The magnet of 5 will be energized, closing the tors key E, the operators set being shown generally at D; By operating the "key E, the

operator will now be connected to the line through the switch 51- conductor 52+ vthe switch 417* the conductor 58 condenser 54 and the portion 55 of the cord circuit 33'- 34J- 25 20 26 35-- 34 the condenser 5.6, switch 46 conductor %7 switch 58. Over this-circuit the operator at station IILwho employs the set I), and the subscriber at X'converse, and the op erator learns what station is wanted by the calling subscriber at X. V

The magnet of the relay 4 was energized when the connection between the cord and the line I was completed by inserting the plug P into the jack J in the well known manner, such circuit being as follows: from battery through winding 61 of such magnetconductor 62 55 33+ 34 25*- 20 22 26- 35'+ '3l' conductor 63 to winding 64: ofthe magnet 4;. This magnet When'actuated closed a switch 66 for a purpose to be described and opened a switch 67 in the circuit of the relay 68, preventing the same from being energized at this stage of the proceedings, another switch 40 in the circuit of the relay 68 having been closed when the magnet of 3 was energized. i r a First, we will assume that it isthe station at Y that the-subscriber at X desires, which, for convenience, will be called the first party, and who is provided with a signal at S adapted to'respondto current produced by the generator at B hen the relay was energized, a circuit was completed for the magnet ofthe relay 6 as follows: ground at 70 battery 7l-- magnet of 6- conductor 72- switch 7 3- switch 74 conductor '75?- now closed switch 148-: conductor 76* conas to convey thatinformation to her.

ductor 7'? switch 7:8 now .closed switch (3.6 conductor 79.resistance 8()- conductor 81 switch 82 to ground 83 The magnet of the relay 0 closes the switches 81 and 85, completing a circuit for the lamp 80,

as follows: ground 87 8'I1'-- conductor 88-- conductor 89 switch 90 conductor 91-- switch 92* conductor 93 switch S5- lamp S6- battery 94" to ground 95. The lamp 86 will light and will indicate-to the operator that the circuit is set up to ring the first party,this lamp being so characterized The operator then inserts the plug P, into the jack J,, the tip 33, the sleeve 3%, and the ring 35 registering respectively with the tip spring 34 the sleeve spring 35, and the ring 36' of the jack J A circuit will be completed through the magnets of therelays 8 and 9 as follows: ground 100* Winding of 8- 36- 35 conductor 101- wind ing of9 battery 102*- to ground. The magnet 8 opens the switches 24! and 27 cutting off the line lamp 31 andthe line relay 1 and associate apparatus of the line 111, so as to prevent their enculnbering the line in the future operations. The magnet 9 opens the switch 13, interrupting the circuit of the relay 5, which is made slow acting, that is, the 'switches e6 to 50 inclusive controlled by it are not opened until a short interval of time during which the more speedy relays are operated.

A switch 103 is closed in the circuit of the supervisory lamp 104-, causing the illumination of that lamp over a circuit as follows: ground at '105- 10lswitch 106 103 4P1 to ground 4.5. The magnet 9 will close a switch 107 andopen the switch 82, but not until after the switch 107 is closed, thereby maintaining thecircuit through the switch S2 and the magnet of the relay 0 untilafter the switch 107 is closed. The switch 107 is closed before either any of the switches -16 to 50 inclusive or 82 are opened. A. circuit will. now be completed for the ringing relay T as follows: ground 110 T 111 switch 107 conductor 81 80 79 66- 78 77* 76+ 48- 74 73- c 71 70, such circuit, as explained, being maintained for a short interval ofthe time after the switch 107 is closed or until the relay T has attracted its arinatures, thereby closing for itselfa locking circuit through the switch 112, as follows: 110 T- 111 107 S1 79-. 66- 78 112 113- 115 battery at 115- to ground at 116. The magnet of T' also opened a switch 117 for a purpose to be described, interrupted the strand 118 of the cord circuit by opening the switch 119 and closed switches 120 and 121 in the ringing circuit. The ringing now takes place over the following circuit: from ground 122 121 at, 355* 26 s 25 34 33-- switch 12Q--- the magnet on? the relay hook 21, closing the switch 130 switch 131* switch 1352-- ringing machine R, to ground at 133. This current until the subscriber at'Y responds by rcthe switchthrruigh the talking set, thereby admitting to the circuit current-of character which causes the operation of the magnet of the relay M0 to close the switch 1-31. The current which courses through this circuit and through the signal S, was incapable of causing the mag net 130 to close 13%. When 13-1 is closed, a short circuit is completed about the magnet T through the connuctor 135, the switch 13-!- to ground at 136. Instead of the current which heretofore passed through T passing through T, it will now pass through the short 135, so that the magnet T will be deenergized and its arinatiilre and the switches controlled thereby restored to the condition illustrated in the drawing.

hen the subscriber at Y responds, the relay F will also be operated, opening the switches 17S and 100. The opening of the switch 106 extinguishes the lamp 104: and the opening of the switch 1'78 breaks the cir cuit of the relay T. The subscribers now carry on their conversations over the limbs of the two line circuits and the strands of the cord circuit, and when the conversation is terminated, restore the receivers to the hooks, breaking the circuits of the magnets -iland F and causing the lamps 188 and 10 t to be lighted, which signal the operator to withdraw the plugs 1 and P, from the jacks J and J which she will do, restoring the apg iaratus to the condition indicated in the drawing.

Second, assuming that it is the party at Z on the line TU who is wanted. F or conrenience, we will call the party at Z the second party. This party is provided with a signal which is arranged to respond to current from the ringing machine it hftcr the operator has learned that it is the party at Z that is wanted, she closes a switch 1-10 by operating a key, here shown as a foot pedal key a, which completes a circuit through the winding; of the magnets G and H as follows: ground 111- 1410 4:2 magnet of G conductor 14-.3 switch 50- con ductor 14A winding of T conductor 1-15 79 now closed switch 66- 78- i'0 ;l-8-- 75 7at- 73 72 6 71-70. The winding of G will be enen'g'ized, opening the switch 02, closing the switch l t-Sand opening the switch 14:9 and closing the switch 50. The 1(Blt1 it will lock itself up over a circuit as follows: S7-- 81- S3 148 G 1--l2 and to bat tery and ground as described in connection with the circuit through the switch 140. Owing to this arrangement. the relay it will remain energized after the hey a has been released. circuit wi', .lso iJQCUEDiflL-kiltti for moving the receiver 20 from O -the second party lamp as follows: 87 84+- 88 151- 150- 152 153 second party lamp (Z battery 9i to ground 95 such lamp indicating to the operator that the apparatus is set up for the ringing of the second party. The magnet of 6 closed a switch 84S5, as previously described. The magnetof the relayI-I opened the switches 160, 161,162 and 132 and closed the switches163, 164, 165, 166 and 167. A circuit will now be completed to the contacts of the key K for the lamp (Z, in order that the operator may at any time test to find out for what party the connections are set. would be as follows: 95 9st, (Z 166- 163 167 168 to K. The operator then inserts the plug P into the jack J as previously described, causing the actuation of the magnets of 9 and 7 and the operations as previously described. The magnet of H in closing the switch 165 locked itself up over the following circuit: 83 82 81 165+ winding of H 1-i3 through the winding of 6 and to ground at 70, as previously described. After the magnet of T is energized and 5 is deenergized, the circuit of II will be as follows: 110- T 111 107 Sl 165- winding of H- 1-15 79 66- 78- 77 112- 113 114 115 and 116. The ringing circuit will now be as follows: 133 R 167* 131- 130 120 over the line 111 through thesignal S and back to ground at 122, as explained.

When the subscriber at Z has responded, the operation will be the same as previously described, the circuit "of H being broken when T is deenergized and the system being restored to normal when the plugs are withdrawn from the jacks.

Assuming that the party at U is wanted, whose station is provided with a signal S which we will call the third party signal, and which is adapted to respond to current from the third party ringing generator, after the connection of the operators set to the calling line, the operator actuates the key I), closing the switch 180 and a circuit through the windings of the magnets I and L, as follows: 181-180-I- 1S2 l9 183- Il 1 15- 79 66 78 77 76 18 75* 7 73 6 71 70. The magnet of I is energized, opening the switches 90 and c and closing the switches 185, 186 and f. The magnet I completes a locking circuit for itself through the switch f, the conductor 89 and the switch 84 to ground at 87, substituting this portion of the circuit for the circuit through the switch 180, so that I will remain energized after the switch 180 is opened. A circuit will also be completed for the lamp (Z which is as follows: ground 195 (Z conductor 196 186 14.9 88- 81- ground 87. The illumination of this lamp indicates to the operator that the apparatu is set for the third. party.

This connection The energization of the magnet at L will i 7 open the switches 131 and'16 and close the switches 200, 201 and 202- The closing of the switch '201 completes a locking circuit fol L from ground 83-582 81-201- to? L. The closing ofthe switch 200 completes a circuit for the lamp 6Z2 up to the contacts of the relay K for test purposes. The operator then inserts the plug P into-the jack J which causes the actuation of the magnets of 9 and T and completes a new circuit for the magnet L around through the switch 112 nd the key 114. Ringing then takes place from ground 183 R,,- 162 202+ and as previously described, the operation being the same as in connection with the other; parties.

Assuming that it is the fourthparty that is wanted, both a and Z2 will be operated, causing the actuation of the four magnets G, H, I and L overthe'circuits described; A circuit will now be completed for'the lamp (Z as follows: 190 (Z, 191 185 150 151- 88- S- 87 The ringing current from the machine B will pass as follows from ground 133 R 1210* 166 202- through 130, the operation thenceforth being the same as described in connection with the other parties.

If at any time the operator after setting up the connection of a particular frequency for any party desires to change it to another party, the connections can be knocked down by operating one of the switches 300 or 301 which causes the interruption of the circuit of 6 and the apparatus dependent thereon. If at any time the operator afterhaving set up the connections for calling a certain party desires to test to determine that party, it can be done so by operating the key Kywhich completes a circuit for that one of the lamps 86, CZ,.(Z1 or 6Z2 for which the connection has been completed,thereby indicating which of the parties is being called whenithe plug is inserted. i v

All of the apparatus below the line IV-IV is common. to a plurality; of cons necting means or cord circuits. I preferably. provide a key K for each of the cords.

I have illustrated this particular embodiment of my invention and these details for the purpose of better describing the invention. I do not wish to be limited either to the embodiment or to the details,qas it will be apparent to any one skilled in the art that numerous and extensive departures may be made both from this form and from these details without departing fromthe spirit of. the invention.

I claim I v 1. In a telephone system, a calling telephone line, a called telephone'line, a plurality of connective circuits having answering and calling connective switches, a relay operated when connectionis made by means of the answering switch of a connective circuit ne'ct each of said generators to thecord cir' with a callingtelephone line, a plurality of sources of signaling current, a plurality of ringing keys common to a plurality of connective circuits and adapted to be associated witha particular connectivecircuit by said relay, mechanism to indicate which of said keys has been operated, and means operated by the closure of the calling connective switch to disassociate said keys from the particular connective circuit. 1

2. In a telephone syste1n, a calllng telephone line, a called telephone line, a plural ity of cord circuits for coiniecting telephone lines together, each cord having an answering switch and a calling-switch for connecting it to a telephone line, a relay operated when connection'is made by means of an an swering switchof a cordcircuitwith a calling telephone line, a plurality of ringing generators, each adapted to produce a cur-' rent'of a certain characterlstiqmeans to concuit to supply ringing current to the called line, said means 1nclud1ng selective keys common to a plurality of cord circuits, each key adapted to be associated-with a particu lar cord circuit by said relay, apparatus toindicate which generator is connected tothe cord circuit and meansoperated by theclo sure of the calling switch to disassoc'iate said ke s from the articular cord circuit employed;; s p

3. In a telephone system, a calling telephone line, a called'telephone line, a plural ity of cord circuits for connecting telephone.

lines together, each cord being provided with an answering switch and a calling switch by" which it may be connected to a telephone line a rela I 03c 'atedflvhen connection is made by means of the answering switch of a cord circuit with a calling telephoneline, a

plurality of ringing generators, each adapt ed to produce a current of a certalnfrelay, means operated by the closure of the calling connective switch to disassociate said selective key from the connective circuit employed and apparatus independent of said means for disassociating said selective key from'said connective circuit.

5. Ina telephone system, a calling telephone line, a called telephone-line, a plurality of cord circuits each having an answering switch and a calling switch for connecting said cord to telephone lines, a relay operated when connection is made by means of the answering switch of a cord with a calling a named key from the quency for operating signals onthe called line lneans including a plurality of keys for connecting each generator to the cord on cuit, apparatus including a plurality of signals controlled by saidfkeys for indicating which generatoris connected to the cord,

said keys being common tea -plurality of cordsand adaptedto be associatedwith the particular cord employed by saidrelay and means operated by the closure of the calling switch to disassociate said key's tromthe particular cord employed. i r

4'. In a iZGlGPhODGLSYStBIH, a calling telephone line, a called telephone line, a plural ity of connecting circuits having answering and calling connective switches, a' relayop-" erated when connection ismade bymeans' of the answering switch of a connective circuit line, a ringing genera-tor, meansto connect the rlngni'g generator to the l1ne, locking apparatus for locking said means, said ineans'including a key common to a plurality of cords and adapted to be associated with a particular cord by said relay, a sec ond key controlled by the operator for interrupting the connection of the generator with the cord and means operated by the closure of the calling switch to disassociate said first employed.

6. In a telephone system, a main station, a plurality of substations, telephone'dines leading from said main station to said" substations, signal bells on said telephone lines, a connective circuit at the main station having answering and calling connective switches, a signaling generator at the main station for applying s1gnal1ng-current from operated by said magnet under the control of "the 'QHSWGIHIg COIHiBCtIVG switch and rcndered inoperative" by apparatus under the control of the calling connective switch.

7. In a telephone system, a main station, telephone lines leading from saidmain station to substations, one of said telephone.

lines being a calling line and another of said telephone lines being a called line, a plurality of substations for said called line, a signal bell for each of said substations adapted. to be operated by ringing current of a (lIStlIlCtlVG character, a plurality of means at the main station for producing currents of distinctive characters, a connective circuit at the main station having '1 l i H H flanswerlng and calling connective switches,

a plurality of signaling lamps at the main stationeach associated with one of said currentprodilcing sources;- one of said lamps with a calling telephone "line, a selective keycommon to a plurality otconnect'ive circuits and adapted to be associated with aparticu-" lar connective circuitemplbyed by saidre trol of the answering connective switch, sai d answering connective switch at the same time automatically associating one of said "current producing sources With the conned particular cord circuit being operate'ttby mechanism under the coirtive circuit, manually operated means under thevcontrol of an attendant operator ior substltutmg a second current producing means for the first current producing means initially associated withthe connective c1rcuit and means under the control of said manually operated means for simultaneously substituting a second slgnal lamp for the initially operated signal lamp to indicate the particular current producing means atthe time associated withthe connective circuit and means underthe control of the calling connective switch forv completing the circuit from thecurrent producing-means associated with the connective circuit tothe called line. A a

8. Ina telephonesystem, a main station, a vplurality of lines leading from said main station to substations, one of said lines being a calling line and another of said lines being a calledline, .a'plurality of signal bells on said called line, each adaptedto be operated with current of a distinctive character, a plurality of means at the main station for supplying said currents each of a switch under the control of said answering connective switch for associating said common apparatus with the partlcular connectivc c rcuit being used to make a connection betweenthe calling and called telephone lines, relays associated with said connective circuit to retain the selection of the particular current supplying means in its association with the connect ve circuit, and

means operated by the connection of the V calling connective switch with the called telephone line to disassociate said common apparatus from theparticular connective circuit, thereby extinguishing said common signal lamp, said. relays retaining theselected vcurrent supplying means in itscasscv ciation with the connective circuit and a relay operatedwhen said connection is made to complete a circult between said current supplying means and said called lineto operate a particular signal. bell on ,the.

called line.

9. In atelephone system, amain station, plurality of linesleading from said main station to substations, one of; said lines heing a calling line andanother of said lines being a called line, a plurality of signal bells onisaid called line, each-adapted. to be operatedwith cu'rrentof a distinctive character,.i-a plurality of means at the :main station forsupplying said currents eaclrof a; distinctive character, a plurality of connective circuits at the main station for associating calling and called lines by means of 2111-1 swering and: calling switches, apparatus commonto agroup 101. said connectivecircuitsfor selectinga particular current supplying means for any one of saidconnective circuits, a plurality ofmanually" oper: ated switches associated'with said apparatus for initiating said selection,rmeans un-' dervthecontrol of one of said switches'for I disestab'lishing, a prior selection ofcurrent supplying means, means under the control of one of said switches forestablishing a difierent; selection of current supplying means, a plurality. of signal lamps for indicating the particular character of current selected, said signal lamps being also commonto therconnective circuits,.amagnetic switch under the controlof said answeringconnective switch for associating said common apparatus Wlth the particular connective circuit being used to make a connection,

between the calling and called telephone lines, relays associated with said connective circuit ,to retain the selection of the particular current supplyingmeansin its association. with the connective circuit, andhmeans operateolfby the connection of the, calling connective switch with the called telephone;

line to disassociatesaid common apparatus fromv the partlcular connectlve' circuit, thereby extinguishmg said common signal lamp,

said relays retaining ,the selected current supplying means in its association with the connective circuit and a relay operated when said connection ismade to complete a cir: cuit between said current supplying means and said calledline to operate aparticular signalibellon the called lineil0. Inatelephone system comprising a main'station, a plurality of substations, a

plurality of linesleading from said main station to saidsubstations, one-of-said telephone llnes be ng a callinglin'e and another of said lines beingvaicalled line, said called-t line having a;plurality of substations each a with an associatedsigna l bell, an answering switch for connecting oneof a group of corinective circuits to the calling line and a calling switch for completingthe connection ,be-

naling generators to selectively operate a particular signal bell OIlfthG called line, a relay in the conne'ctivecircuit for controlling the connectionof aparticular source of signaling current, a plurality of. signaling tween the particular connective circuit being used and the called line,a pluralityof Sig-12o lamps common to the group of connective circuits for indicating the particular sourcev of s gnalmgcurrent which s at the time be-:

ing applied tolthesigna l bells of the called line, and a manually operated switch under Leanne? with the particular connective circuit for operating the particular signal lamp to in dicate the selected signaling current at any time subsequent to the completion of the connection. 7

11. A telephone system, a plurality of con-, necting circuits therefor, a plurality of ring ing relays for each of said connecting circuits, a key common to said connecting circuits for controlling saidringing relays, and,

common indicating means for said. connect ing circuits controlled by said ringing relays. V

'12. A telephone system, a plurality of cord circuits therefor, a plurality of ringing relays for each of said cord circuits, a common key for controlling said ringing relays,

said ringing relays.

18. In a telephone system, a plurality of connecting circuits therefor, relays in. said connecting circuits and individual thereto, a key common to a plurality of said connecting circuits, means to associate said key with any of the connecting circuits, said key con trolling the relays of said connecting circuits, visual indicating means common to a plurality of said connecting circuits and adapted tobe controlled by the relays of any connecting circuit 1 V 14. A telephone system, a pluralityof signaling circuits therefor, relays in each of said signaling circuits, common means therefor,

controlling means in each of said connecting circuits, a plurality of alternative circuits therefor, said signaling circuits being common to a plurality of connecting circuits, said relays controlling said signaling circuits.

15. In combination, a plurality of telephone connecting circuits, common} key. means for setting up a predetermined rlngingcondition in any of said connecting circuits, and common signal devices for indi:

ating the ringing condition set up", in any connecting circuit. 1

16. In combination, a plurality of telephone connecting circuits, means for setting up a predeterminedringing condition in any of said connecting circuits, commonsignal devices for indicating the ringing condition set up in any connecting circuit, and individual key means controlling said signal devices. i

17. A telephone system, a plurality of connecting circuits thereftn, a plurality of ringing relays for each of said connecting circuits, a common key for. controlling said ringing relays, and a common signal circuit, said ringing relays having contacts in said common signal circuit. 7

18. A telephone system, connecting circuits thereforwa setof ringing generators therefor, a set of signals therefor, each of said signals corresponding toaparticular and a common signal circuit controlled by relays for each of lug relays of a cord circi'ut,

common key said selective ringing relays, a

necting circuits,

my a

one of said ringing generators, said ringing generators and said signals being couunon to a group of connecting circuits.

19. A telephone s stcni, a group of connecting circuits therefor, a common set of ringing generate-r a common set of s each signal of the set correspmulim particular ringing generator of the set, electro-magnetic controlling mechanism in each connecting circuit for selecting a ringing generator and its associated signal, and a commonset of keys for interchangcably controlling said electromagnetic mechanism.

ol' tale of sesaid (21 nectiug and a plurality of branches therefor. said branches being controlled lay said selective relays. 7

22. ll telephone system, a plurality of cord ciri'tuits therefor, a pluralitvof ringing relays for each of said cord circuits. 5. coni mon set of keys for controlling said ringing relays, a common signal circi it Cfil'iilOllGll by. said ringing relays and a licjv individual to the cord circiuts. said hey controlling said signal circuit 23. A telephone svsteu'r. a plurality of cord circuits therefl'ir, a plurality of ringing l cord circi'lits, a common set of keys for controlling said ringing relays, means in each of said cord circuits for associating said set of h with the ringod a couuuou signal circuit controlled by said ringing relays,

9A. A telephone system. a plurality of; coune,. "1g circuits therefor. a plurality of selective ringing J'L avs for each of said con-- necting circuits, a common scoot keys conti'olling said selective relays, and means in dividual to each of the connecting circuits for assoclatuig said common set of keys with common set of signals, a source ofcurrent, and circuit connections for associating said source of current with one of said signals, said circuit including contacts of said relays.

25. A. telephone system, a plurality of connecting circuits therefor, a plurality of selective ringing relays for each of said cosa common set of keys controlling said selective relays, and means individual to each of the connecting circuits for associating said common set of keys with circuits, a common key for said ringing relays, a common group of signals, and a key 1n each of said connecting circuits, said key and sald rmgmg relays of any of the con- .necting circuits being adapted to control the said common signals.

27. The combination with a plurallty of telephone lines, a plurality of connecting circuits therefor, common key means for.

setting .up a predetermined ringing condition in any of said connecting circuits, a connection switch for one of said connecting circuits to connect said connecting circuit to a telephone line, a relay in said connecting circuit, said relay being under the control of said connection switch, and circuit connections including contacts of the said relay for dis-associating said common key means when said connection switch is operated.

28. The combination with a plurality of telephone lines, av plurality of connecting circuits therefor, common key means for setting up a predetermined ringing condition in any of said connecting circuits, a connection switch for one of said connecting circuits to connect said connecting circuit to a telephone line, a relay in said connecting circuit, said relay being under the control of said connection switch, circuit connections including contacts of the said relay for disassociating said common key means when said connection switch is oper 'ated, common signal devices for indicating the ringing condltion set up in any connecting circuit, and individual controlling means for said signal devices.

29. In combination, a plurality of telephone connecting circuits, interchangeable key means for setting up a predetermined ringing condition in any of said connecting circuits, signal devices for indicating the ringing condition set up in any connecting circuit, and individual key means controlling said signal devices.

30. Atelephone system a plurality of telephone circuits therefor, a plurality of ringing relays for each of said connecting circuits, interchangeable key means for controlling the ringing relays of any of said connecting circuits, and a common signal circuit, said ringing relays having contacts in said common. signal circuit.

31. A telephone system, connecting cir cuits therefor, a set of ringing generators therefor, acorresponding set of signalsflas I sociated therefor,,each of the signalsofthe set corresponding to 'aparticular ringing generator of the set, electro-magnetic means in each of the connecting circuitsfor associating aparticular ringing generator with the connecting circuit, means to simultane' i ously condition one of the sand signals correspondmg to the selected rmging generator'for operation, said ringing generators andsald signals being common to a plurality of connecting circuits.

32.111- combination, a plurality of contion, a connection switch "for said connecting circuit, dis-associating means for said common key means under the control of said connection switch,'a common signalcircuit,

and a plurality of branches therefor, said branches being controlled by saidelectromagnetic means. r r

33'. A telephone system, connecting cirtherefor, a set of signalstherefor, ringing cuits therefor, a set of ringing generators relays in said connecting circuits controlling said signals, a common set of-keys for operably setting up said rlnging relays, said set of'keys-also controlling a set of common relays, said common relays controlling said signals and said ringing relays.

3a. A telephone system, connecting circuits therefor, a set of rmging generators therefor, a set of signals therefor, ringing relays in said connecting circults controlling said signals and said ringing generators, a common set of keys controllingsald set of ringing relays, said set of keys also control 1 linga set of common relays, said common relays also controlling sald signals. 7

35. A 1 telephone system, a plura connecting circuits therefor, a plurality of ringing, relays foreach of said connecting circuits, a plurality of common associated relays, a common signal circuit, said common signal circuit being; under the alternate control of said ringing relays and said common associated relays.

36; In combination, a plurality of telephone connecting circuits, common key means for setting up a predetermmed ringing condition in-any of said connecting circuits, common signal devices for indicating the ringing condition setup in any connecting circuit and common relay means controlling said signal devices.

lity of In witness whereof, I have signed my name hereunto this 11th day of April, 1916.

FRANK M. SLOUGH.

copies of this patent may be obtained for five cents each, by addressing the, Commissioner of Patents,

Washington, D. G. 

